This paper developed and validated a new measure of support for the Black Lives Matter (BLM) movement among a racially–ethnically diverse sample of college students. The measure focuses on the movement’s principles of Black liberation, intersectionality, and alliance building. Participants included 1934 college students (75% female) from a large public Southwestern university. The factor structure was supported by exploratory and confirmatory factor analyses, resulting in an 18‐item measure, Support for Black Lives Matter, with two underlying factors. Black Liberation includes 12 items representing support for BLM because of awareness of and challenging structural inequality and racism experienced by Black individuals. Intersectional Values includes six items representing support for BLM because it embraces and affirms marginalized populations within the Black community, especially disabled Blacks, queer Blacks, Black women, and Black families with children. Evidence of criterion‐related validity was demonstrated with racial group differences in support of BLM factors. Evidence of convergent validity was supported by significant positive correlations between support for BLM factors and critical consciousness (including awareness of racism, classism, and heterosexism), and negative correlations between support for BLM factors and subtle racist attitudes toward Blacks. Measurement invariance was evident between White, Black, Asian American, Latinx, and Multiracial participants. Implications and suggestions for use of the new measure are discussed.